1. Field of the Invention
This invention relates to a thrust bearing device used for receiving thrust of a motor shaft, in a motor provided with a worm of a reduction gear on the motor shaft, for example.
2. Description of the Prior Art
Heretofore, there has been used a thrust bearing device for a motor as shown in FIG. 3, for example.
A motor shaft 101 of a motor is provided with an armature wound with wire at one end thereof not shown in FIG. 3, and is formed with a worm 101a at the middle part thereof forming a reduction gear together with a worm wheel. And another end of the motor shaft 101 is supported rotably by a bush 103 disposed in a housing 102 of the motor.
In the housing 102, a thrust plate 104 to be in contact with another end of the motor shaft 101 and a spring 105 to energize the motor shaft 101 in its axial direction through the thrust plate 104 are provided as a thrust bearing device for the motor so as to receive thrust of the motor shaft 101 caused by working of the motor.
However, in the aforementioned conventional thrust bearing device of the motor, the motor shaft 101 is allowed to move until the spring 105 is compressed entirely when thrust load is applied on it, and the motor shaft 101 is apt to become rickety since it is movable extensively. And the movable range of the thrust plate 104 with the motor shaft 101 is wide, and worse still the thrust plate 104 is not always compressed uniformly, therefore the thrust plate 104 is apt to be inclined against the center line of the spring 105, and there is a problem since the spring 105 and the thrust plate 104 are waiting in durability and reliability.